Microstructures and tensile properties of hot extruded Mg–5Li–3Al–2Zn–xRE(Rare Earths) alloys

Abstract

As-extruded Mg–5Li–3Al–2Zn–xRE(Rare Earths)(x=0, 0.5, 1.5, 2.0) alloys were prepared and analyzed by X-ray diffraction, Scanning electronic microscopy and tensile tests performed at room temperature(RT) and 200°C. Microstructure transformation and the resulting tensile properties of as-received alloys subjected to homogenization treatment were also studied. The results show that the RE addition in the alloys causes the formation of Al2RE/Al3RE, and they co-exist with primary α-Mg and AlLi phase in the alloys. Moreover, RE addition can improve the RT tensile properties of the alloys, while it has little effect on the improvement of elevated temperature tensile properties. Furthermore, the mechanical properties of the alloys after homogenization treatment are worse than those of as-extruded alloys.